Well drilling bit



" Q Patented 22, 19 38 v UNITED? S T AI ATENT v O CE This inventionrelates to a well drillingtool and-relates more particularly to adrilling bit tor use in the rotarymethod oiwell drilling. A gen- .eralobject of the inventionis to' provide rpm tical eflective :wellgbitembodying an improved 'and very eillcient combination of cutters.

Another object otthis invention is to provide f a rotary well drillingbit in which the-outer or peripheral portion oiflthe well bore isdrilled by 10 rotatable cutters of one type and the remaining innerportion of the bore is :drilled by rotatable cutters of: anothertypewhereby the maximum efliciency of both forms or cutters is obtained.

Another object of this invention is to provide a well Abit embodyingroller type cutters-rotatably supported for rotation about substantiallyhorizontal or only partially inclined axes to cut an, annular channel atthe peripheryoi the wellbore bya rolling and crushing actiomandembodying scraper type cutters-"supported for rotation aboutnearlyvertical axes to cut away the remaining portion of theboreby ascraping orshearing' action. I

Another object of' this invention isto provide aiwell bit or thecharactermentionedinwhich the slightly tilted or nearly verticalshearingtype cutters are self-sharpening" through their en gagementl with theearth formatio AnotherAobject of this invention is to provide a bit ofthe character mentioned. in which the slightly tilted or nearly verticalscraping type cutters are forced to rotate and; therefore,

very eflicientand long.wea.rmg

Another object of this "invention 'is Atoms-wid A a novel and' highlyeflicien't- ,forniof rotatable cutter for a welldrilling bit whichcutteris intended to be supported for rotation about a ;-nearly vertical axisand embodies reaming cutting teeth toassure its rotation; I

A40 Another-object 01' this invention is to provide a well bit oi thecharacter mentioned in which the crushing roller cutters are mounted or:pins which are dependably supported at both their inner and outer ends.

Another object oi this invention is to provide a well drilling bit ofthe characterfmentioned in which the nearly vertical rotatable scrapingcutters are devoidAof teethat their lo'we'r ends and; therefore are notas liable to. failure asthe .60 to hed nearlyverticalcutterslheretotoreintro A. Another object 01 this invention istoprovide a well drilling bit of the charactermentioned in which astreamoi, circulation fluid is discharged A downwardly irom within the lowerend oieach scraper type cutter to clear its cutting edge or mud andcutti ll,

The various objects and features of my invention will be fullyunderstood from the following detailed description of a typical form 5 eand application of the invention, throughout which description referenceismatle to the acri 1 is side elevation org-theimnroved bit provided bythis invention with a portion in ver- 10 tical cross section"to'ilhistrate the rotatable mounting clone or the "scraper type cuttersFig. 2 is an enlarged i'rsamentaryvertical de- .tailed seamen view takenmbstantifll! as indicatiad by line 29-! on Fig; 1. 3 is atransisversedetailed sectional View taken as by lineH on Fig. i and Fig. 14 isa bottomelem e meba- A a 1 A a Y The-rotary well-drilling bit oi'thepresent invention includes. senerslly.A a shank or ll, 20 crushingroller type cutters I i rotatabiy' su on the body It, and shearing ortype cutters i2 rotatably supportedtonthe II.

The shank or body" "is to beconnected with the-lower end of arotsrydrilling 2 string. Thebody ll may be integral and may be generallycylindrical. Means is proyidedatthe upper end of the bodyl'l-tofa'cllitate its connec-' tion withthe well drilling string. Inthe'vpar-v- It toreceive spin on the lower end oi the drillingstring."1he.'lower-} end portion or the body ll maybe enlarged in diameten- IIis "provided with pairs avings or legs is and II to receive and carrythe cutters II and their mount- In theparticular embodiment ofthejinvention illustrated there "are two diametrically opposite pairsoflegs lland II, The legs i4 and I! are integral with the'body llandpmlct 40 downwardly and outwardly from its'lower end. 'I'he'legs IIare the outer legs 'oi the pairs. and may be somewhat thibker than theinner legs I}. The legs ll and II oi each pair aresub'stantiallyparallel and are prqvided attheir inner sides 45 with opposing raisedbearing surfaces it, and i 6', respectively. The lower outer corners orthe outer legs II are bevelledto besubstantially vertical and flatshoulders I! are provided on the The lower inner away'and flat shouldersAll are provided on the lower ends of,- these. legs;

' .I'hebody n is provided withspaced is to carry the means for rotatablysupporting the cutters i2. In the embodiment of the inventionillustrated there are two substantially diametrically opposite bosses l3projecting downwardly at 5 the lower end of the body in. The bosses IIare partially cylindrical and their longitudinal axes are slightlyinclined downwardly and forwardly with respect to the direction ofrotation of the bit. Due to the pitch or slight inclination of thebosses i3 they are not directly diametrically opposite but have theiraxes at opposite sides of a diametrical plane. The lower ends of thebosses l3 are flat and are normal to their longitudinal axes.

The cutters II are operable by a crushing action to form an annular cutor channel in the peripheral portion of the well bore. The cutters IIare in the nature of roller cutters. The roller cutters II have centrallongitudinal openings i9 and flat normal ends. Peripheral cutting teeth23 are provided on the cutters ii. The teeth 20 preferably overhang orproject outwardly beyond the outer ends of the cutters The innerandouter corners of the teeth 20 are preferably bev-- ellecl off, asillustrated in the drawing. The teeth 23 may be straight or spiralled,if desired or found practical. The two roller cutters Ii may beidentical in size and shape.

The invention provides effective dependable means for rotatablysupporting the roller cutters |I between the spaced legs l4 and IS. Themeans for rotatably supporting the cutters include bushings 2|. Thebushings 2-|,are tubular cylin drical members and are provided at theirinner ends with annular thrust'flanges 22. The flanges 22 areadapted tobearagainst the surfaces l5. Extensions or lugs 23 are provided on thethrust flanges 22 and cooperate with the shoulders to prevent rotationof the bushings 2| and to transmit upward thrusts directly to the legsI5. The outer end portions 2| of the bushings 2| are reduced'in diameterand carry thrust washers 24. The washers 23 are adapted-to bearoutwardly against the thrust surfaces It. The cutters i are rotatablysupported on the bushings 2| between the flanges 22 and the washers '24.In practice the cutters I may be rotatably supported on the bushings 2|through roller bearings 25. The flanges 22 and the washers 24 serve tospace the cutters II from the legs I3 and ii and to transmit end thruststo the legs;

Shafts or screws 26 are passed inwardly through openings 21 in the legsl5 and have their 3 outer portions threaded in openings 28 in the legs,II. The openings 21 and 28 are inclined downwardly and inwardly havinglongitudinal axes normal with the surfaces Il and I5. screws 26 areprovided at their inner ends with heads 28' bearing outwardly againstthe legs IS. The headed and threaded screws 26 serve to tie together thelower portions of the legs I4 and IS. The screws 23 pass through thebushings 2| to support the bushings between the legs It and IS. Notches29 are provided in the outer sides of the legs I at the openings 28 andend parts of the screws 26 are peened into these notches 29 to lock thescrews against unthreading. The cutters supported as just described arerotatable about downwardly and inwardly inclined axes and projectdownwardly beyond the lower ends of the legs i4 and i5 to act on theformation at the bottom of the well bore and project slightly beyond theouter sides of the legs I4 to assist in cutting the bore to gauge. It isbelieved that it 75 will be understood by those skilled in the art how"uated or varying in external diameter.

tubular.

edges 32.

The

the roller cutters operate to cut an annular groove in the periphery ofthe well bore by a crushing rolling action.

The cutters.|2 are an important feature of the invention being of novelshape and construction. 5 The invention, as illustrated, includes twocutters i2 which may be .alike in size and shape. The cutters i2 aregenerally cylindrical though grad- The cutters J2 are preferably, thoughnot necessarily. 10

As illustrated in the drawing each cutter l2 has a central longitudinalopening 30. The upper ends of the cutters ilarefiat and normal. Inaccordance withlthe invention the cutters I2 ,are"'substantiallycup-shaped having depressions 15 or central sockets'3l in their lowerends.

sockets 3| are comparatively large in diameter and are provided to formor leave annular cutting edges 32 at the lower ends of the cutters. Thecutting edges 32 are the principal cutting 20 edges of the cutters l2and have shearing or scraping engagement with the earth formation aswill be hereinafter described. The extreme lower ends of the cutters l2are bevelled upwardly and away from the cutting edges 32. The 25 sockets3| in the lower ends of the cutters I2 provide or leave cylindrical.walls at the lower ends of the cutters and the edges 32 occur at thelower ends of these walls.

The walls or surfaces of the sockets 3| are 30 hard faced with tungstencarbide, or the like, to provide the cutters with long wearing cuttingThe sockets 3| are comparatively deep so that the edges 32 are very longwearing. As the edges 32 scrape along the bottom of the well 35 bore themetal behind or surrounding the edges 32 being softer than the hardfacing comprising the edges 32, wears away, leaving the edges 32 sharp.Due to the depth of the sockets 3| the edges 32 automatically remainsharp until the 40 tubular lower walls of the cutter |2 are almostentirely worn away.

In addition to the cutting edges 32 the cutters |2 are provided withreaming teeth 33. The upper portions of the cutters l2 are enlarged in45 external diameter and longitudinally extending grooves 33' are formedin these enlarged portions of the cutters to form or leave the reamingteeth 33. The grooves 33 forming the teeth .33 are preferably ofsubstantial depth to extend into 50 the bodies of the cutters I2. Thereaming teeth 33 extend from the upper ends of the cutters |2 tocircumferential lines spaced slightly above the upper walls of thesockets 3|. In the drawing the teeth 33 are shown as straight or axial,it 55 being understood that the reaming teeth 33 may be pitched or,spiralled, if desired. The teeth 33 being formed in the enlarged upperportions of the cutters i2 have active longitudinal edges for areslightly inclined downwardly and forwardly relative to the direction ofrotation of the bit. Sockets or openings 34, having the desired slightinclination, enter the bosses l8 from their lower ends and extendupwardly into the body i0 proper. The longitudinal axes of the openingstatably supported on so that they may be easily and quickly removed forresharpening or replacement. "The body Ill is subjected to littleor nowear and'the various Having described o y atypical preferred form andapp cationormy, invention I do not, wish be limited or restrictedto thespecific details forth, but "wish for rotation about asubstantiallytransverse axis make an annular cut in the and positioned to peripheralportion oi the "well, and a cutter rotatably supported on the body'forrotationabout an axis inclined downwardly and slightly .i'orwardlyrelative to the direction of rotation vof the bit and having ascrapingon the inner portion of the well.

'2. A rotary well drilling bitincluding, a a roller cutter rotatablysupported on the bodyfor rotation about a-substantially transverse axisand positioned "to makean ahnularcut rin the peripheral portion orthewellyand a cutter rotatably supported on the body i'onrotation aboutan axis'inclined downwardly and forwardly relative tothe direction of"rotation of the bitythe last mentioned cutter having 'a continuousscraping edg 'jfor acting on the' innerportionof the wellbor; b

3. A rotary well drilling bit including, a body, a roller cutterrotatably supported on the body for rotation about asubstantiallytransverseaxis and positioned to make an annular cutin theperipheral portion or the well, and acutter' rothe body forrotationa'bout an axis inclineddownwardly and forwardly rel ative to thedirection of rotation of the bit. the last mentioned cutter having acontinuous scraping edge for acting on' the inner portion of the wellbore, and reaming teeth for contacting the side wall oi the bore toeffect its rotation.

an axis inclined V tive to the direction of rotation of the bit, therethe cutter ing an endless x 4. A rotary well drilling bit including,body; and a substantially cylindxicalcutter supported on the lower endofthe body for rotation about downwardly and forwardly relabeingan.opening in the lower end of leaving a-wall of tubular form'whose lowerend presents an annular-scraping edge.

5. A- rotary well drilling bit including, a body,

and a-cutter supported bodyjtor rotation about I wardly and slightlyforwardly relative to the direction 01' rotation of the bit, the cutterincluding an endless. scraping edgeon its lower end. I

6. A. rotary well n and afcutter supported on the lower end of the onthe .lower end' 01' the body 101- :rotation, .abon'tan axis inclineddownwardly and slightly forwardly relative to the di-" rection oirotation or the bit, the cutter includand reamingteeth above,

7. A rotary said edge.

ing in its lower end edge for acting an axis inclined downdrilling :bitincludins, a body.

scraping edge on its lower end, well drillingbit including, a

.4 2,111,781 7, on the tool prevent the cutters l2. from being and acutter supported on the lowe end of the subjected toexcessive feedpressures. body for rotation about a nearly. ertical axk, The cutters li ,and the cutters I2,are dependthere being an opening in the lower endof the ably supported for independent rotation about cutter leaving awall of tubular form which preindividual axes. The cutters are supportedsents an annular scraping edge. said cutter ineluding hard facingmaterial lining the said socket whereby said wall wears away through useto maintain said edge sharp. l i

8. A rotatable cutter for a well drill including, a cutter body intendedto be supported for rotation about "a generally vertical axis, said bodyhaving an opening provide a cutting edge; v 9. A rotatable cutter for awell drill including, a cutter body to be supported for rotation about anearly vertical axis, said body having an opena well, a rotatablecutterhaving a scraping edge I at. its lower end and axially extendingreaming and raisedreaming teeth on the periphery of the teethon itsexternal surface, and means rotatably n y cutter on the lower end of thebody to rotate about a downwardly and forwardadjacent and substantiallyparallelwith the side wall or the bore whereby the said teethengage theside wall to cause rotation ofthe cutter. p a

j 11. A wellbit including, a body to be rotated in a well, a rotatablecutter having a scraping edge at itslower end and axially extendingreaming teeth on its, external surface 01' greater enective edgescrapeou the bottom of the bore and to have its outer peripheral surfaceadjacent and substantially Darallel'with the side wall of the borewhereby the" said teeth engage the side wall to cause rotation 01'. thecutter.

12. A well bit including a body having a fluid opening, a pin carried bythe body and projecting from its lower'end, and a cutter rotatable onthe pin about adownwardly and forwardly inclined axis,'said cutterhaving a'socket in its lower end leaving anannular scraping cutting edgeforacting on the bottom wall of the bore, said pin having an opening forconducting fluid from the first mentioned opening to said socket.

13. A'rotary well drill including, a body having a pair-oispaceddepending legs, a pin extend- ..ing between said legs to have its endssupported thereby, aroller cutter on said pin rotatable about a,substantially transverse axis to act on the bottom wall of the well, andascraping cutter rotatably supported 1 by the body to rotate about aslightly downwardly andtorwardly inclined axis to act on the bottom wallof the well. 14. A rotary well drill including, a body, sub

stantially diametrically opposite pairs 01' spaced ported on saidpinsiorrotation about downwar ly andginwardly inclinedaxes to have rollingcontact withthe peripheral portion of the bore, and cutters rotatabLvsupported by the body between said-pairs oi legs to rotate about 34 arenormal to the lower ends of the'bosses l3 a with.. the openings and theopenings 34 are tapered being of upwardly diminishing diameters. Themeans for rotatably carrying the cutters |2 include studs or pins 35arranged upwardly in the openings 34. The upper portions of the pins 35are tapered to properly fit the openings 34.

Means are providedv for removably lockingthe pins 35 in the openings 34.*Transverse openings 35 are provided in the bosses I3 and intersect-orpartially join the openings 34 adjacent their outermost walleportions.-The openings 36 are elongate in cross section and have their majortransverse axes incl'ined downwardly and outwardly. Notchesfl areprovided in the exteriors of the pins 35 to complement or communicate35: Wedges 33 are arranged or driven'in the open'ings35 to cooperatewith the notches 31. The end portions or at --least the small endportions of the wedges 33 are turned over to prevent accidentaldisplacement of the chamber 50 is provided in wedges from the openings35. The wedges 38 cooperate with the notches 31 to dependably lock thepins against displacement from the openings 34 and serve to hold thepins against rotation. The pins 35 project downwardly from the bosses l8and the cutters 2 are rotatable on the projecting portions of the pins.The pins 35 project through the openings 30 in the cutters l2 and haveannular flanges at their lower ends to prevent displacement of thecutters. The flanges 40 are preferably received in annular re-.

cesses4i in the upper walls of the sockets 3|. Hardened thrust washers42 are preferably interposed between the upper endsof the cutters |2 andthe lower ends of'the bosses l3. Suitable dowels 43 hold the thrustwashers 42'against r0- tation.

The cutters l2 are rotatably supported on the pins 35 to rotate aboutapproximately vertical axes, the axes of rotation of the cutters beingslightly inclined downwardly and forwardly relative to the directrotation of the bit. Thus the lower ends of the sockets 3| on thecutters l2 are open and trailing portions of the cutting edges 32 haveshearing or scraping engagement with the formation at the bottom of thewell bore. The active portions of the cuttingedges 32 are insubstantially the same horizontal plane as the edges of the teeth 20where they contact the formation. The scraping cutters l2 are positionedand mounted so that their peripheral surfaces are substantially verticalwhere they are opposed to and adjacent to the side wall of the well boreso that these surfaces move in a circular path larger in diameter thanthe circular paths of the outermost surfaces of the bosses l3 and legs|4. Owing-to this disposition of the cutters H the reaming teeth 33 comeinto positive cooperation with the earth formation and are substantiallyvertical as they engage the side wall of the well. The engagement of thereaming teeth 33 with the side wall of the well bore reams the bore togauge and effects the positive rotation of the cutters l2 about theirindividual axes. This independent rotation of the cutters l2 renderstheir edges 32 more effective and long wearing.

The invention provides means for flushing the cutters H and I2 ofcuttings and mud. A fluid the body II! at the lower end of its socketl3. The chamber 50 receives the circulation fluid pumped downwardlythrough the drilling string. Ports 5| are provided in the body l5 andextend downwardly -tion with the chamber from the chamber 55 to thespaces between the adjacent legs l4 and I5. The ports 5| are inclineddownwardly and outwardly and direct the circulation fluid against thecutting teeth 23 of the cutters II. The upper ends of the openings partsof. the tool is connected with the lower end of a suitable well drillingstring. The drillin'g string is lowered into the well and is rotated andfed downwardly in the'usual manner to advance the bit into theformation. The roller cutters II are formed and positioned to cut arelatively narrow channel in the earth formation at the periphery of thewell bore. This cut formed by the cutters II is slightly less than thedesired gauge of the well bore. The cutters op erating by a crushing orrolling action take or transmit a substantial portion of the feedpressures on the bit relieving the cutters l2 of excessive feedpressures.

The cutting edges 32 of the slightly tilted cutters |2 have scrapingengagement with the bottom wall of the well bore within the cut made bythe cutters ll. The cutting edges 32 being endless or annular havesmooth even engagement with the formation to effectively cut awaythesame by a scraping action. As above described, the side walls of thesockets 3| are hard faced with tungsten carbide or the like to providethe cutting edges 32. As the tool operates the relatively soft metalsurrounding and backing the cutting edges 32 wears away leaving theedges 32 sharp. The metal surrounding the edges 32 trails the edges 32as they engage the formation and these trailing parts of the cutters |2are worn away more rapidly than the edges 32. Further, asmall core maybe left standing between the cutters i2 and the lower outer parts of thecutters I2 may be worn away due to their engagement with the core. Thelower outer portions of the cutters |2 are relatively close to thecenter of the bit and are moving at a relatively high velocity when theyengage the core and, therefore, wear away rather quickly. This wearingaway of the metal about the edges 32 automatically maintains the edges32 sharp. Thus the cutters l2 are self-sharpening through use.

The reaming teeth 33 have a larger effective diameter than the edges 32and cutters II and engage the formation at the side wall of the wellbore to cut the bore to the desired gauge. This reaming engagement ofthe cutting teeth 33 with the side wall of the well bore effects thepositive rotation of the cutters l2 making the cutting edges 32particularly efilcient and long wearing. It will be noted that thecutters'i2 present endless or annular principal cutting edges 32 foracting on the formation at the bottom of the well bore and do not haveprojecting blades liable to breakage or failure. The cutters II and I2are spaced and related to assure the smooth even operation of the tool.The roller cutters II in taking a substantial portion of the down feed15 In the operation of the bit provided by this 1 invention the body Itcarrying the various other downwardly and slightly forwardly inclinedaires to have scraping contact with the bottomwall 0t the bore. i

.15. A rotary well drill including, a body, sub:

' stantially diametrically opposite pairs of spaced legs projecting fromthe lower end of the body, pins supported by said legs, roller cutterssupported on said pins for rotation aboutdownwardlyand inwardly inclinedaxes to have rolling contact with the peripheral portion of thebore, andcutters rotatably supported by the body between said pairs of legs torotate about downwardly and slightly forwardly inclined axes, the lastmentioned cutters having scraping edges at'their lower ends contactingthe bottom wall or the well and reaming teeth contacting the side wallof the bore.

contacting the side wall of the bore.

16. A rotary well drill including, a body, sul1- stantlallydiametrically opposite pairs of spaced legs projecting from the lowerend of the body,

plns supported by said legs, roller cutters supported on said pins forrotation about downwardly and inwardly inclined axes to have rollingcontact with the peripheral portion of the bore, and l cutters rotatablysupported by the body between said pairs of legs to rotate aboutdownwardly and slightly forwardly inclined axes, the last mentionedcutters having annular scraping edges at their lower ends contacting thebottom wall of the well, and reaming teeth of longer efiective diameterthan the lower portions of saidcutters JOHN H.

